RESULTS:

The results showed that 68.4% of the samples were positive by IHC, 42.1% were positive by FISH, and 63.9% contained activating kinase domain mutations. EGFR mutations were more frequent in non-smoking patients (p=0.008), and EGFR mutations were associated with EGFR FISH positivity (p<0.0001). When using 10% positivity and 2+ as cutoffs, EGFR protein expression was significantly correlated with EGFR FISH positivity (p=0.012) and EGFR mutations (p=0.008) after Bonferroni correction.

CONCLUSION:

EGFR protein expression, EGFR copy number and EGFR mutations were closely related to each other. Standard methods and interpretation criteria need to be established.

The consistency of three biomarkers. A-C: Case 1, three biomarkers were all positive in the same case, A: IHC positive(3+), B: FISH positive (amplification), C: Curves for exon 19 using the Scorpions ARMS method, if only one ascending curve showed the wild-type, more than two ascending curves showed the mutation. Two ascending curves in this case indicated mutation(the left curve represented wild type, the right curve represented mutant, exon 19 deletion). D-F: Case 2, three biomarkers were all negative in the same case. D: IHC negative, E: FISH negative(low trisomy), F: mutation negative(one ascending curve indicated EGFR wild type).